1. Field of the Invention
The present invention relates to a fuel tank valve structure, and more particularly, to a fuel tank valve structure for hybrid vehicles which can control emission gas under various driving and stop conditions of plug-in hybrid vehicles.
2. Description of Related Art
Hybrid vehicles generally used in the relates art are driven by power from an internal combustion engine and power from electric motors, such that they are under interest due to fuel saving and environment-friendly features.
However, since both of the internal combustion engine and the electric motors for generating the power are equipped in the vehicle, the weight of the vehicle increases, and power for operating the electric motors is required, the internal resistance increases and the output is reduced. Further, energy is lost in the process of converting and storing electric energy.
Therefore, the plug-in hybrid vehicles that can be operated by charging the vehicle batteries at common houses to use an internal combustion engine and electric motors as independent power sources have been developed, in order to make the best use of electric vehicles while reducing energy loss during the process of converting the energy in the vehicles, and using the efficient internal combustion engine used in the related art.
Since the driving type changes while increasing the driving ratio of the electric motors in the plug-in hybrid vehicles, emission increases due to the decrease of the amount of engine fuzzy, such that measures against this problem are required.
That is, as shown in FIG. 1, a fuel limit vent valve apparatus for controlling emission gas and determining the amount of refill in refilling vehicles has functions of allowing for refilling by sending the air and emission gas in the fuel tank to the canister in refilling and controlling the amount of fuel injection by stopping sending the gas in the fuel tank to the canister when the fuel tank is fully filled with fuel, and has an additional function of preventing fuel from overflowing the canister or preventing the fuel from leaking out of the fuel tank.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.